Turbulence modeling and the physics of the intra-cluster medium

TL;DR

This paper introduces FEARLESS, a novel turbulence modeling scheme combining SGS and AMR techniques, applied to cosmological simulations of galaxy clusters to better understand turbulence and entropy distribution in the intra-cluster medium.

Contribution

The paper presents FEARLESS, a new numerical scheme for turbulence modeling that improves the simulation of turbulent flows in galaxy clusters.

Findings

Turbulence production correlates with merger events.

Minor mergers cause localized turbulent dissipation.

Entropy in cluster cores is increased in FEARLESS simulations.

Abstract

FEARLESS (Fluid mEchanics with Adaptively Refined Large Eddy SimulationS) is a new numerical scheme arising from the combined use of subgrid scale (SGS) model for turbulence at the unresolved length scales and adaptive mesh refinement (AMR) for resolving the large scales. This tool is especially suitable for the study of turbulent flows in strongly clumped media. In this contribution, the main features of FEARLESS are briefly outlined. We then summarize the main results of FEARLESS cosmological simulations of galaxy cluster evolution. In clusters, the production of turbulence is closely correlated with merger events; for minor mergers, we find that turbulent dissipation affects the cluster energy budget only locally. The level of entropy in the cluster core is enhanced in FEARLESS simulations, in accord with a better modeling of the unresolved flow, and with its feedback on the resolved mixing in the ICM.